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Publication numberUS2331803 A
Publication typeGrant
Publication dateOct 12, 1943
Filing dateMay 2, 1941
Priority dateMay 2, 1941
Publication numberUS 2331803 A, US 2331803A, US-A-2331803, US2331803 A, US2331803A
InventorsSchlaanstine Raymond F
Original AssigneeHercules Powder Co Ltd
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Method of producing rosin esters
US 2331803 A
Abstract  available in
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Claims  available in
Description  (OCR text may contain errors)

Patented Get. 12, 1943 z,331,ao3

UNITED' STATES N-r OFFICE METHOD OF PRODUCING ROSIN ESTERS Q No Drawing. Application May' 2, 1941, Serial No. 391,483

8. Claims.

This invention relates to an improved method of producing rosin esters and more particularly relates to an improved method for producing glycol esters of a rosin.

The esterification of rosin with ethylene glycol by heating the rosin and ethylene glycol under reflux conditions at temperatures of about 200 C. has been described. By such a process a. very extended heating is required to produce-esters of relatively low acidity. Use of catalysts such as zinc dust and boric acid have been suggested to accelerate the esterification rate. Even with use of a catalyst the esterification is so slow as to require abnormally long heating periods. Furthermore, use of a catalyst in the esterification is not very practical since it is necessary to remove the catalyst from the final ester and also since the catalysts generally have a deleterious effect on the rosin or rosin ester such as efiecting its watersensitivity, its melting point, etc. Removal of the catalyst from the finished ester is also attended with dimculties and complete removal is not easily obtained. Similar difliculties are encountered in the esterification oi rosin with other lowtion with the rosin quite rapidly andthereby does not volatilize from the reaction vessel. At the completion of the heating period any unreacted glycol or other volatfle matter may be removed by distillation, preferably under reduced pressure.

By carrying out the esterification of a rosin with an aliphatic glycol having no more than 3 carbon atoms in the above manner, it is possible to prepare the glycol ester without use of. a cataglycol having no more than 3 carbon atoms with low acidity in a shorter heating period than has been possible heretofore. I

The rosin which may be used in the process may be any of the various grades of wood rosin or gum rosin or the resin acids contained therein,-

as for example, abietic acid, pimaric acid, sapinic improved method of heating rosin with aliphatic I 'glycols having no more than 3 carbon atoms to provide esters of low acidity. It is another object to provide a method of esterifying a rosin with ethylene glycol which will provide an ester of low acidity without use of an appreciable excess of the glycol and with use of a relatively short heating period. Other objectsof the invention will appear hereinafter.

The above objects are accomplished in accordance with this invention by heating a rosin with not over about one-half the equivalent proportion of an aliphatic glycol having no more than 3 carbon atoms to-a' temperature in the range 0! about 250 C. to about 290 C. and thereafter continuing the heating atatmospheric pressure at the above temperatures and adding further amounts of the glycol gradually at such a rate which will permit rapid combination with the rosin without appreciable volatilization until the equivalent amount or slight excess thereover has been added. The heating is then continued until an ester of low acidity is produced. By

carrying out the esteriflcation in the above manner the heating is carried out at a temperature at which rosin is mere reactive with the glycol and thereby a considerable reduction in reaction time is made possible. Byadding the glycolgradually during the heating it undergoes partial combinaacid, etc. Modified forms of rosins may also be employed such as for example, hydrogenated rosin, polymerized rosin, heat-treated rosin, rearranged rosin such as Hyex rosin, etc. All such materials are classified as rosins for the-purposes of describing the invention. The glycols to which this invention is applicable comprise the lowboiling aliphatic glycols of 2 and 3 carbon atoms, such a class of glycols being represented by ethylene glycol, propylene glycol and trimethylwith the method of this invention the rosin is heated with a small amount of the low-boiling glycol, usually about A, of the equivalent amount, and not overabout of the equivalent amount,

to a temperature within the range of 250 C. to

290 C. After a short heating at this temperature iurther amounts of the glycol are added gradually in a continuous stream or in aliquot proportions at such a rate that the amount of refluxing of the glycol will be held to a minimum.

A reflux condenser will be preferably employed to return any condensed glycol to' the reaction vessel. The rate at which the additional glycol may be added will depend to a certain extent on the' actual temperature of esterification employed. Alternatively, the ,Josin may be heated to within ever, esters of the above glycols and particularly ethylene glycol and rosin having an acid 'number below are easily obtainable according to the described method without use of more than a slight excess of the glycol.

The following examples are illustrative of the various embodiments of the invention.

Example I Twenty-four hundred, and seven parts by weightof N wood rosin and 67.5 parts by weight of ethylene glycol were heated together to a temperature of 255 C. in about 2.5 hours. At this point an additional 67.5 parts by weight of ethylene glycol were added and the temperature maintained at 255 to 260 C. After an additional 2 hours of heating the third addition of 67.5 parts by weight of ethylene glycol was introduced and the heating continued at the same temperature. After 2 more'hours heating the last addition of 60 parts by weight of ethylene glycol was made and the heating continued at a temperature of 260 to 270 C. Five hours after the last addition of ethylene glycol the acid number of the ester was 26. By continuing the heating for 8 hours after the addition of the last ethylene glycol the acid number had dropped to 10. -At this point the pressure was reduced to about mm. and the volatile materials removed "by distillation. The ethylene glycol ester obtained had an acid number of 10, a melting point (drop) of 61 C. and a Lovibond color of 21 Amber.

Example II Two thousand parts by weight of distilledhydrogenated rosin having a saturation corresponding to about 70% of both double bonds, of the rosin and 50 parts by weight of ethylene glycol were heated together to a temperature of about 270 C. in 1 hours and the heating continued at this temperature for 2 hours. An additional 50 parts by weight of ethylene glycol were then added and the heating continued at the same temperature. After 6 hours heating at 270 C. the third addition of 50 parts by weight of ethylene glycol was made. Again after 9 hours heating at 270C. the fourth addition of 50 parts by weight of ethylene glycol was made. The heating was then continued at a temperature within the range of 270 to 285 C. for 6- Example III Five hundred parts by weight of N wood rosin and 17.5 parts by weight of propylene glycol were heated together to a temperature of about 280 C. in 1 hours and the heating continued at 280-288 C. After 30 minutes heating at the latter temperature a second portion of 17.5 parts of propylene glycol was added and heating continued. A third portion of 17.5 parts of propylene glycol was added after 1 /2 hour heating at 280-288 and a fourth portion of 17.5 parts of propylene glycol after 2 /2 hours heating at the same temperature. An additional 10 parts of propylene glycol were added after 10 hours heating at the same temperature. After 13 /2 hours heating the ester was sparged with a rapid stream of carbon dioxide for V2 hour to remove any unreacted glycol, and the ester cooled. The total heating time at 280 to 288 C. was thus approximately 14 hours. The propylene glycol ester obtained had an acid number of 21, a melting point (drop) of 74 C. and a Lovibond color of 38 Amber.

It will be apparent from the above description and examples that the improved process of producing glycol esters of rosin provides a much more satisfactory method than has been known heretofore for producing such esters of low acidity. It makes it possible to obtain an ester of low acidity from a low-boiling aliphatic glycol in a shorter reaction time and without use of catalysts or superatmospheric pressure.

It will,be understood that the details and exampleshereinbefore set forth are illustrative only and that the invention as broadly described and claimed is in no way limited thereby.

What I claim and desire to protest by Letters Patent is:

1. The method of producing. an ester of a rosin and an aliphatic glycol having no more than 3 carbon atoms which comprises heating a rosin with not over about one-half the equivalent amount of the said glycol to a temperature in the range of about 250 C. to about 290 0., continuing the heating at atmospheric pressure at the aioresald temperature and adding further amounts of the glycol gradually at such a rate as will permit rapid combination without appreciable volatilization, and continuing the heating until an ester of low acidity is produced.

2. The method. of producing an ester of a rosin and an aliphatic glycol having no more than 3 carbon atoms which comprises heating a rosin with not over about one-half the equivalent amount of the said glycol to a temperature in the range of about 250 C. to about 290 C.,

continuing the heating at atmospheric pressure at the aforesaid temperature and adding further amounts of the glycol gradually at such a rate as will permit rapid combination without appreciable volatilization and until no more than a slight excess over the equivalent combining proportion has been introduced, and continuing the heating until an ester of low acidity is produced.

3. The method of producing an ester of a wood rosin and analiphatic glycol having no more than 3 carbon atoms which comprises heating a wood rosin with not over about one-half the equivalent amount of the said glycol to a temperature in the range of about 250 C. to about 290 C., continuing the heating at atmospheric pressure at the aforesaid temperature and adding further amounts of the glycol gradually at 'such a rate as will permit rapid combination without appreciable volatilization and until no more than a slight excess over the equivalent combining proportion has been introduced, and continuing the heating until an ester of low acidity is produced.

4. The method of producing ane'ster of a gum rosin and an aliphatic glycol having no more than-3 cagbon'atoms which comprises heating a gum rosin with not -over about one-half the equivalent amount of the said glycol to a temperature in the range of about 250 C. to about 290 C., continuing the heating at atmospheric pressure at the aforesaid temperature and adding further amounts of the glycol gradually at such a rate as will permit rapid combination without appreciable volatilization and until no more than a slight excess over the equivalent combining proportion has been introduced, and

continuing the heating until an ester of low acidity is produced.

5. The method of producing an ester of 'a hydrogenated rosin and an aliphatic glycol having no more than 3 carbon atoms which comprises heating a hydrogenated rosin with not over about one-half the equivalent amount of the said glycol to a temperature in the range of about 250 C. to about 290 C., continuing the heating ataatmospheric pressure at the aforesaid temperature and adding further amounts of the glycol gradually at such a rate as will permit rapid combination without appreciable volatilization and until no more than a slight excess over the theoretical combining proportion has been introduced, and continuing the heating until an ester of low acidity is produced.

6. The method of producing the ethylene glycol ester of a wood rosin which comprises heating.

a wood rosin with not over about one-half the equivalent amountof ethylene glycol to a temperature in the range of about 250 C. to about 290 C., continuing the heating at atmospheric pressure at the aforesaid temperature and adding further amounts of ethylene glycol gradually at such a rate as will permit rapid combination without appreciable volatilization and until no more than a slight excess over the equivalent combining proportion has been introduced, and continuing the heating until an ester of low acidity is produced.

7'. The method of producing the ethylene glycol ester of a gum rosin which comprises heating a gum rosin with not over about one-half the equivalent amount of ethylene glycol to atemperature in the range of about 250 C. to about col ester of a hydrogenated rosin which comprises heating a hydrogenated rosin with not overabout one-half the equivalent amount of ethylene glycol to a temperature in the range of about 250 C. to about 290 C., continuing the heating at atmospheric pressure at the aforesaid temperature and adding further amounts of ethylene glycol gradually at such a rate as will permit rapid combination without appreciable volatilization and until no more than a slight excess over the equivalent combining proportion has been introduced, and continuing the heating until an ester of low acidity is produced.

RAYMOND F. SCHLAANSTINE.

Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US2748093 *Nov 3, 1951May 29, 1956Harshaw Chem CorpScreen vehicle comprising diphenyl, unmodified hydrogenated rosin, and its glycol esters
US4248770 *Jun 11, 1979Feb 3, 1981Arakawa Kagaku Kogyo Kabushiki KaishaProcess for preparing stabilized rosin ester, and pressure-sensitive adhesive composition and hot-melt composition
US4302371 *Jul 17, 1980Nov 24, 1981Arakawa Kagaku Kogyo Kabushiki KaishaStabilized rosin ester and pressure-sensitive adhesive and hot-melt composition based thereon
US4758379 *Nov 14, 1986Jul 19, 1988Union Camp CorporationProcess of preparing polyol esters of rosin with excess rosin
US6562888Jul 27, 1998May 13, 2003Arizona Chemical CompanyLight-colored rosin esters and adhesive compositions
EP0270774A1 *Oct 14, 1987Jun 15, 1988Union Camp CorporationImproved process of preparing polyol esters of rosin
Classifications
U.S. Classification530/218, 560/7
International ClassificationC09F1/00
Cooperative ClassificationC09F1/00
European ClassificationC09F1/00